Danny Sullivan has written the ultimate guide to how Google Instant autocomplete suggestions work. He put a lot of time, research and work into this piece, getting facts and confirmation from Google on all of it. Any SEO should really read it, so they fully understand the latest on how it works.
Danny broke it down as follows:
- History of Google Suggestions
- Google uses real searches for the list of suggestions
- Suggestions can vary by Region & Language
- Google uses previous searches for suggestions
- Google ranks suggestions based on popularity and relevance
- Google does de-duplication and spelling corrections
- New, trending and freshness comes into play
- Google removes suggestions for hate or violence, personally identifiable information, porn & adult-content, legally mandated removals and piracy-related suggestions
- Can it be manipulated? Yes.
That is just the bulleted list, check out Danny's post for context, examples, images and more.
Forum discussion at Sphinn.